CreveTec is offering technology, knowhow and products to improve farming methods of shrimp. We focus to improve the nutrition and environment of the shrimp. Shrimp have the potential to grow much faster when they are cultured in ideal conditions. Production of shrimp started a while ago in a very extensive way. Wild postlarvae were stocked in ponds and natural production in the ponds provided for the nutrition of the shrimp. To increase the production per ha, stocking density was increasing and artificial feeds were developed to complement the natural production. As technology and feeds improved, production per ha increased, but also the limits to the system became clear.
Shrimp differ in a lot to other farmed species:
- Shrimp are benthic. They only use the bottom of a pond.
- Shrimp must find the feed by chemical attraction (olfactory sensors). Feeds should leach substances (often useful nutrients) to attract shrimp to the feed.
- Typically, shrimp feed pellets will stay in the water for 15 - 60 minutes before the shrimp consumes them. But they can lie in water for several hours before consumption and should remain water-stable during this time. During this time, feed pellets swell by taking up water and water-soluble nutrients leach out of the pellets. These nutrients are a loss. In semi-intensive farming, shrimp are typically fed 3-4 times/day. This worsens the problem enormously.
- Shrimp are external masticators, meaning that they chew their feed outside their mouth. They are selective feeders, nibbling on pellets and only consume more feed when palatability is OK: When shrimp start consuming feed, they will not ingest the feed at once. They will nibble on it, select the palatable pieces and throw away whatever they don’t like. The uneaten parts are left and will be digested on the pond bottom by bacteria.
- Shrimps are poor digesters. Their digesting system is rudimentary. A lot of nutrients pass their system without being assimilated. For example, the protein efficiency of shrimp is only 15-20 %.
- In nature, shrimps will consume a lot of pre-digested feed, like rotten fish and detritus. Whatever is not assimilated goes back to nature and is recycled. In ponds however, as density of production increased, these excess nutrients became pollutants, using oxygen and degrading into ammonia, hydrogen sulphide and methane, all toxic to shrimp. To get rid of those pollutants, water is exchanged and the pollutants are flushed out of the system. This way, the chance of recirculating them is lost and the feed will never be utilised at this maximum. This is the main reason why feed conversions in shrimp culture are horribly high and don’t show any progress during the last couple of years.
- Shrimps can consume detritus actively or passively. Soluble nutrients will dissolve in the pond water and feed the natural bloom of the pond: phytoplankton, which in turn will feed zooplankton. The shrimp will ingest some of this plankton again. This is what we call natural production of the pond.
- Crustaceans have some unique nutritional requirements such as phospholipids, cholesterol, Phosphate to Calcium ratio. Knowledge of shrimp nutrition has increased during the years, but application in business has been difficult. Semi-intensive farming is not the system that will maximise shrimp efficiency and different shrimp feed qualities have not show substantial differences in the production. Hence, shrimp producers tend to choose the cheapest feed.
The aim is to produce shrimp and other crustaceans in the most ecological way.
This means with optimal utilisation of various resources: water, feed, raw materials, land surface.
All losses (leaching, undigestible food, unnecessary transport of feed, nutrient rich effluents) should be minimized and treated in the following order:
Reduce, Reuse, Recycle
- Reduction of losses: short time between production of feeds and utilisation
- Optimal utilisation: maximum digestibility, good feed quality, feed management
- Treatment and recyling: nutrient recycling through in-pond biological treatment, uptake of nutrients by algae and bacteria
- Effluent treatment: recuperation of nutrients by seaweeds, molluscs, omnivorous fish
- Utilisation of sludges for the production of sea vegetables.
CreveTec will develop technology, alone or with partners, to optimize resources utilisation, step by step.
Crevetec wants to provide a total solution for ecological (and economic) production of shrimp.
This means shrimp will be produced with maximum efficiency of feed and minimum impact on the environment (no effluents). CreveTec can assist you with:
- Consulting for shrimp farming with zero exchange of water, by means of in-pond purification of pond water. Bacterial flocks will return in the pond and recycled by shrimp directly or indirectly. This system can be used for ultra-intensive farming (up to 10 kg/m²) and in existing semi-intensive systems.
- On farm production of tailor-made, high quality feeds. Local (moist) ingredients will be used in the formula together with the necessary imported raw materials and concentrates. Different production systems can be used according to specific conditions on the farm. For small scale production, a cold extrusion system is developped. Focus on those feeds is not low cost, but maximum digestibility/production, and lowest feed conversion.
- Optimisation of feed utilization by close collaboration with the shrimp farmer for feed formulation, logistics, storage and feeding management. We can work with an open formula, which means the farmer can choose with us which quality he wants for his farm and will know how the price of the feed is formed.
- Assistance for existing Aquaculture feed production units: Audit of formulas, raw material sourcing, ingredients to use, production system and quality control.
- Analysis and evaluation of existing shrimp feed brands: leaching of substances.
- Supply of new, innovating raw materials.
- Integrated farming with effluent treatment by ways of growing secundary crops like tilapia, seaweeds of halophytes.
- Contract Research